I would like some guidance on how to import multiple .txt files containing data seperated by comma on a MATLAB GUI. Once the files are uploaded, I have a function that will manipulate all the data from each .txt file.
Any help is appreciated.
The easiest way to import multiple files is to:
Use the file importer GUI in matlab and generate a script after you
selected your preferred parameters
Generate a script (there is a button to generate a script in the importer)
Modify the script with a for loop to load multiple files and save them in a variable (a cell array can handle different sizes of data in each file)
Try uigetfile to launch a dialog for loading files. Set 'MultiSelect' to 'on' in order to select multiple files at once.
Here's an example call:
[filenames, pathname] = uigetfile({'*.txt; *.csv','Comma separated values';...
'*.*','All files'},'Select files','MultiSelect','on');
You will need to check if the user actually selected a file or if they canceled.
If I understand your question correctly, you have a GUI already. In this case you just need to add the above call to your designated callback function (i.e. whatever you click to invoke this file load interface).
Related
I want the user of a script I'm writing to be able to navigate to a file containing their data and to load the data into the workspace. For example, if a csv file contains two cells with the values 1 and 2 respectively, I want the user to simply choose this file and those two values will be assigned to a variable in the workspace.
I have looked at using:
filename = uigetfile('*.xlsx','*.csv')
But that just returns the name of the file. Perhaps I could construct a full path to where the file they choose is found, and then read it in that way (using xlsread or csvread) but I think I'm probably missing something here. It seems that there should be a more straightforward way of doing it.
I believe that you're looking for the uiopen() function. This function will:
Open dialog box for selecting files to load into workspace.
On default, this function will display in a file explorer dialog box with the filter set to all MATLAB® files (with file extensions *.m, *.mlx, *.mat, *.fig, *.mdl, and *.slx).
However, you can import data from data files like CSV files and spreadsheets as well. Simply select the (All Files) option for the Files of Type field.
Once you've selected the data file you're interested in, you will be prompted with another GUI object that previews the data you are about to load into MATLAB's workspace. If you're satisfied with the format of the variables presented in the preview, simply hit the green check-mark at the right-side of the tool-box ribbon in the GUI object and, huzzah, all of the data file's contents have been loaded into separate variables (named according to their respective headers).
Alternatively, though this is undeniably a longer-winded and uglier approach, if you'd like to use the filename returned from uigetfile('*.xlsx', '*.csv'), you could use the importdata() function. This will output a struct that contains each of the variables from your data file as a separate field:
[filename, pathname] = uigetfile( ...
{'*.csv;', 'CSV file (*.csv)';
'*.xlsx', 'Excel Spreadsheet file (*.xlsx)'; ...
'*.*', 'All Files (*.*)'}, 'Pick a File to Import');
full_filename = fullfile(pathname, filename);
[A, delimiterOut] = importdata(full_filename);
I saved my command line by first clicking on it and pressing ctrl+s and MATLAB saves a .mat file.
Now I want to open it in a text form in order to remember what I did in my command line the other day.
Is there a way to do that?
Saving a .mat file from the command window saves all of the variables that currently exist within your workspace within a binary .mat file. There is no information about the commands that were used to generate these variables in this file format therefore it cannot be automatically extracted from another program.
If you need to get information about what commands were run, you can look at your command history to see this. If you need to programmatically access this file you can look in MATLAB's preference directory for the file named history.m or history.xml on newer versions.
type(fullfile(prefdir, 'history.m'))
If you need to keep track of what commands you run in the future, you can use diary at the top of your script or beginning of your session to log all commands and associated command line output to a plain-text log file which would then be accessible to other programs.
diary('mylogfile.txt')
Suppose two different Matlab users share a computer and they each want to be able to save and load their own Matlab paths. (Or, a single user wants to use different paths at different times.) What's the easiest way to handle this?
Should there be multiple pathdef files? Alternatively, should they each have a script that calls restoredefaultpath and then uses addpath to add new paths?
You can use the startup.m file for that.
When starting up, Matlab executes the file matlabrc.m, which is the master startup file, and is common for all users. Among other things, this file
Sets the first entry of the path as the user-folder of the current user, that is, the user that started Matlab. (This is done by calling pathdef, which in turn calls userpath); and then
Looks for a startup.m file in the path, end executes if it exists.
Therefore you can place a user-specific startup.m file in each user's folder, and Matlab will run the appropriate file depending on which user started Matlab. In that file you can set the path on a per-user basis, and do other user-related stuff.
I'm new in GUIDE in MATLAB. I have two different problems:
I would like to save in a .mat file all variables (about 1000) from workspace using a button in GUI in MATLAB. How can I do?
I have a button where after press on it I'm able to load a specific .mat file from my path, always using GUI, but I would like that the variables contained in this file, became presents in the base workspace.
In other words, I have a button, "LOAD", in GUIDE in MATLAB where I can load a .mat file, and the variables contained in the .mat file must be loaded into the 'base' workspace when the button is clicked.
Please help me.
For your first question, I would suggest just putting a command like save('filename.mat'); in the "Save" button's callback. But what variables? If they are in the base workspace, see my answer to your second question below.
To load data into the base workspace, you might try the evalin command:
evalin('base','load(''filename.mat'')');
The 'base' argument tells it to run the command in the base workspace.
If your file name is in a variable:
fname = 'filename.mat';
evalin('base',['load(''' fname ''')']);
Alternatively, you could use sprintf:
loadCmd = sprintf('load(''%s'')',fname);
evalin('base',loadCmd);
I have a problem loading multiple images at the same time using matlab. Could anybody me?
How about writing a small program?
'uigetdir' [http://www.mathworks.com/help/techdoc/ref/uigetdir.html] to let user to select the directory where image files are.
'dir' and determine the names of the files in that directory.
'listdlg' to create a list of files on a GUI, with 'SelectionMode' as 'multiple'
check the file extension (you can do this before #3 also to show only image files in the list.)
count (N) how many image files the user wants to load and plot ('length' of the selected filename string).
loop for N times and go through the list of filenames, and open each one with the appropriate loader function (by determining the file extension of each file before loading)
as you load the data from the files, you can plot them however you like either in a single figure or multiple.
Best,
Y.T.